Physically, no, he just got blood on his uniform. Both knives landed on opposite sides of his head when she fell on top of him. Judging by his performance, though, the encounter probably caused some emotional trauma, which might indicate that it was the first time he had to kill someone.
The writers haven't done much to make him more than occasional comic relief and the guy who gives the initial rundown at each crime scene, so I would be highly surprised if he got included in the Scooby Gang. I wouldn't want him to join, either, unless his character were to become more useful and interesting first.